1. Field of the Invention
The present invention relates to a heat transfer system, and more particularly to a fluid heat transfer system. More specifically, the present invention relates to a fluid tight multi-compartment fluid heat transfer system for pumping and circulating a heated working fluid therein.
2. Known Art
Prior art heat transfer systems that utilize motors to drive impellers to circulate a heated working fluid usually comprise several distinct and physically separate compartments with the motor residing in one compartment and the impeller in another separate compartment. The impeller is usually located in a tank containing a heated working fluid that circulates throughout the heat transfer system. A drive shaft is provided that operatively connects the motor to the impeller that extends through the walls of each compartment. To secure the shaft, rotating seals are mounted in the compartment walls. The motor and impeller are separated to protect the motor from the extremely hot working fluid being circulated through the other parts of the heat transfer system.
One disadvantage of multi-compartment heat transfer systems are that leaks of hot working fluid may develop outside of the rotating seals securing the drive shaft. Typically, these rotating seals are comprised of an opening formed in the compartment wall to receive the drive shaft having a layer of ceramic material applied to the surface of the opening. The drive shaft may also have a ceramic layer applied along a portion of the surface that rotates within the compartment wall opening. As the drive shaft rotates with respect to the opening, the impeller forces hot working fluid through the heat transfer system by raising the pressure of the fluid. Exposing the rotating seal to pressurized fluid invariably results in leakage of the hot working fluid from the compartment housing. Not only is the leakage inevitable, it is necessary as this leakage acts as a lubricant between the drive shaft and compartment wall opening surfaces. However, this leakage of hot working fluid can cause damage to areas surrounding the system and can create a dangerous situation.
Additionally, because of the inability to isolate heat from the working fluid and the motor in prior art systems, these systems are only capable of maintaining working fluid at or below a temperature of 600xc2x0 F. Finally, these types of prior art systems are quite large and expensive to produce. Therefore, there appears a need in the art for a multi-compartment heat transfer system that uses hot working fluid without the inherent disadvantages of the prior art devices.
Among the several objects, features and advantages of the present invention is to provide a multi-compartment heat transfer system that circulates a heated working fluid without leaking.
Another feature of the present invention is to provide a heat transfer system that can maintain a heated working fluid at extremely high temperature levels.
A further feature of the present invention is to provide a heat transfer system of compact construction.
An additional feature of the present invention is to provide a heat transfer system that creates a balanced operating load for the impeller.
Yet a further feature of the present invention is to provide a heat transfer system having dimpled surfaces for improved heating efficiency.
Yet another further feature of the present invention is to provide a heat transfer system having a guiding region secured within the tank that rotatably carries the impeller such that working fluid may leak between the impeller and the guiding region without leaking from the heat transfer system.
These and other objects of the present invention are realized in the preferred embodiment of the present invention, described by way of example and not by way of limitation, which provides for a fluid heat transfer system having a novel motor and fluid heating tank arrangement.
In brief summary, the present invention overcomes and substantially alleviates the deficiencies in the prior art by providing a fluid heat transfer system comprising a tank having an inlet and an outlet for pumping and circulating a fluid therethrough with the tank further defining a guiding region for receiving a rotatable shaft. The rotatable shaft operatively associates with a motor at one end, while the other opposed end is a free end. A hollow tube surrounds the rotatable shaft with the shaft and tube extending into the tank. The opposed free end of the rotatable shaft is connected to an impeller For circulating the fluid. The impeller is rotatably carried by the guiding region within the tank so that the fluid may flow between the impeller and the guiding region without leaking outside of the tank.
Additional objects, advantages and novel features of the invention will be set forth in the description which follows, and will become apparent to those skilled in the art upon examination of the following more detailed description and drawings in which like elements of the invention are similarly numbered throughout.